MacStories recently featured a crazy-good-but-temporary deal: $15 for a refurbished Mophie Juice Pack Air for iPhone 4. If you're not familiar with the Air, it's a rechargable power case that allows you to essentially double your phone's battery life. Normally, these things go for at least $60 brand new, and we just happen to be going on a trip to Disney World in a couple weeks, so I couldn't pass this deal up.

In fact, I bought two of them; a white one for myself (I wanted a red one but they were sold out already), and a black one for my wife. They just arrived in the mail a couple days ago, and I wanted to share my thoughts so far.

This is the first time a case of any kind has touched my iPhone 4S in the year-and-a-half that I've owned it. I used to keep an Incase Slider on my old iPhone 3G, but the 4S is just too beautiful to cover up, in my opinion. I only mention this because the sudden additional heft and weight the Air adds to my iPhone makes it feel like a tank. Nerd alert: it's like Iron Man's Hulkbuster armor compared to the standard model.

It still fits in my pocket of course, but it creates a noticeable bulge (the jokes write themselves) and I constantly sense the phone's presence, unlike when it's sans-case and I forget it's even there. On top of that, while it's not an ugly case, it's definitely not beautiful either. I have a feeling I won't be keeping the Air on my phone all the time. More likely, it'll stay in my bag and only be brought out as needed.

I also don't much care for the fact that the sleep button becomes very recessed in this case, when it normally sticks out a bit at the top. A button that is normally quite easy to use becomes much more difficult to access because you have to curl your finger around the case's thick plastic and down into the recess.

I don't mean for this to be a negative review though. Aside from its quirks, the Air has a lot of nifty features:

There's an on/off toggle for the battery component of the case. This means you can keep the phone in the case all the time without the phone constantly being charged. Somehow I'd never heard about this toggle, and merely assumed people just put the cases on as needed. Seems so obvious now that I've got one in my possession.

Rather than drilling mic/speaker holes all the way through the bottom of the battery, they've opted to place a couple of ports on the front of the case to redirect audio toward you. Audio doesn't seem to be muffled in my early tests, but we'll see over time.

On the bottom of the case resides a row of 4 status indicator LEDs and a button. Push the button, and the LEDs will light up to show you how much charge the battery is currently holding. While the case is being charged (which is done via a miniUSB > USB 2.0 cable), the lights will indicate how far along the charge is, as shown in this Vine video I made.

When your iPhone is in the case and you've got the case plugged in, I believe both items will charge up simultaneously, and you can still sync your iPhone with iTunes if you want. Haven't tested this yet, though. Keep in mind that this is the iPhone 4 Juice Pack; I've heard that sync functionality has been removed on the newer Air models but I'm not entirely sure on that so do your research if you're going to buy a new one.

Overall, I'm pretty happy with my purchase so far. These cases won't be seeing a ton of use just yet, but when we go on our trip I expect to put them through their paces quite a bit.